1. Field of the Invention:
The present invention relates to a band guiding structure for a packing machine for feeding a band from a pre-feed roller to a band forward-reverse unit and for guiding a band which is either fed or reversed in a pool box.
2. Description of the Background
Conventional packing machines, which guide a band from a pre-feed roller around a band guide arch and which package goods positioned in the band guide arch by wrapping with the band, are popularly used. Such packing machines include a pool box for temporarily storing the band between the pre-feed roller and the band guide arch.
The pre-feed roller continuously pulls the band in a band guide path during a banding operation. Thus, the band is fed forward in the banding operation. The band also reverses in order to band the goods tightly in the banding operation. Consequently, if the band cannot go forward or is reversed while being continuously fed, the band must have a way to escape from the band guide path. The pool box provides an escape for the band. That is, the band guiding structure guides the band to the band guide arch without storing the band in the pool box when the band is fed for the first time. The band guiding structure, however, will guide the band into the pool box when the band is either fed forward or reversed.
A large capacity of pool box is preferred in view of the function of the pool box. A large amount of band will indeed be stored in the pool box during the banding operation.
As shown in FIG. 1, one example of background packing machine provides a guide plate 104 for introducing and guiding the band B. The guide plate 104 is rotatably attached to a pool box 101 and is arranged between a pair of pre-feed rollers 102 and a band forward-reverse unit 103. In the example, the guide plate 104 is operated by hand or by electric power.
That is, the guide plate 104 is normally positioned as shown by a solid line in FIG. 1. This is the position when the band B is fed for the first time. Once the band B is used by the packing machine, the guide plate 104 will rotate as shown by the dotted line in FIG. 1. Thus, an entrance 105 of the pool box is opened and the guide plate 104 expands into the capacity of the pool box 101 for storing the band B.
Disadvantages of the background packing machine are now described hereinafter. A device having a guide plate 104 operated by hand has a disadvantage that the guide plate 104 must be operated whenever the band B is replaced or re-inserted into the pre-feed rollers 102, so that the operation of the guide plate 104 is troublesome and complicated. If the guide plate 104 is not completely set, the band B may not be correctly introduced into the packing machine, so that some trouble may occur. A device having a guide plate 104 operated by electric power has the possibility that the guide plate 104 is not completely set. As mentioned above, if the guide plate 104 is not completely set, the band B may not be correctly introduced into the packing machine, so that some trouble may occur. The structure having the guide plate 104 operated by electric power also has a disadvantage that the structure is complicated and expensive.